| Guangxi as the biggest province of cassava planting in the country,the cassava starch industry have development rapidly.Wastewater treatment is the one of the key factors for the development of cassava starch industry.Currently,there are many anaerobic treatment technology to deal with cassava wastewater in domestic.IC anaerobic reactor as the third generation anaerobic reactor is highly regarded.The project had mainly improved inner internal circulation system and it was a novel reactor with controlling internal circulation.The experiment obtained the suitable data of operation parameters and studied the development of anaerobic granular sludge,biochemical properties,reaction kinetics.Specific content as follows:1.The research of reactor start-up process.In the startup process of the reactor,HRT was controled 12h,reactor temperature was 35(±1?),pH was 7.6-8.0,and the concentration of wastewater CODcr was 1500mg/L.With gradually increase the CODcr of influent to 8000mg/L,the reactor start-up was completed.The CODcr removal rate increased from the initial 77.2%to 93.73%after start-up completed.Gas production was increased from the initial 5.32L/d to 30.83L/d.VFA was decreased from the initial 4.00mmol/L to 2.40mmol/L,and VFA/ALK was relative stability.The reactor was operated in good condition.2.The research of reactor process efficiency and process parameters optimization.The paper had studied the effects of reactor with controlling reflux ratio,and temperature.Controlled by the corresponding single factor test and combined by future engineering practical application situation,the reactor was identifid the best operation parameters as follows:the reactor temperature T = 25-35 ?,wastewater CODcr=8000mg/L,HRT = 9h,reflux ratio R = 4.Under the operation parameters,the effluent CODcr=650mg/L,CODcr removal rate was 91%,wastewater VFA tendency was 2.55mmol/L,ALK was above 20.00mmol/L,the reactor gas production rate was 24.42L/d,gas generation rate was 0.25m3CH4/kg-COD,and the reactor was running stability.3.The reaserah of the physical and chemical properties and microflora.Using analytical means such as high-throughput sequencing,fluorescence spectrometry algorithms,fourier transform infrared spectroscopy,the development and the physical and chemical characteristics of anaerobic granular sludge were studied,the results were as follows:(1)During the reactor was start up,the particle size of anaerobic granular sludge was increasing,it increased from 1.5mm to 3.2mm,VSS/SS increased from the original 0.18 to 0.65,the organic composition of anaerobic sludge and the activity of sludge was growing.The amount of EPS was increased from the initial 9.10mg/gVSS to 38.60mg/gVSS,and the ratio of polysaccharide and protein changed from 0.42 to 1.76.The infrared spectrum analysis of EPS showed that the 1000-1150cm-1 absorption peak was caused by the functional groups of polysaccharide,the 3000-3400cm-1 and 1630-1680cm-1 and 1520-1550cm-1 absorption peak was caused by the functional groups of protein.It was showed that EPS of anaerobic sludge was mainly composed by the proteins and polysaccharides.Analysised by the three dimensional fluorescence spectrum of EPS,it was appeared coenzyme F420 characteristic peak in the Ex/Em = 420/470nm,and it showed that the performance of anaerobic granular sludge was well.(2)When wastewater CODcr=8000mg/L,T = 35?,HRT =9h,and the controllable inner loop device was opened,reflux ratio R = 4,the physical and chemical indicators of anaerobic granular sludge was the highest,the average particle size was 3.3mm,the density was 1.0498kg/m3,the sedimentation speed was 99.34m/h,VSS/SS was 0.68.(3)The anaerobic granular sludge in different parameters were scaned by a scanning electron microscope observation,it found that the microorganism was different under the different condition,and it mainly was bacillus and staphylococcus aureus strains form.Through the MiSeq high-throughput sequencing and bioinformatics analysis method analyzed the flora composition and biodiversity.Under different conditions,the structure of microbial flora was different.Under the best condition,the main composition of Microflora was the Euryarchaeota(99.66%).Including of the Euryarchaeota,the Methanomicrobia was 44.78%,the Methanobacteria was 54.77%.Including of the Euryarchaeota,the Methanosarcinales was 39.69%,the Methanomicrobiales was 5.09%,and including of the Methanobacteria,the methanobacteriales was 54.77%.4.Reaction kinetics study.(1)In this paper,the static dynamics of cassava wastewater degradation process was researched,and it got the degradation reaction kinetics equation y=42 84.35*exp(-x/2.32)+4146.81.(2)And tests which assumptioned that the first reaction zoneis completely mixed state,the second reaction zone was the plug flow,it deduced the kinetics of substrate degradation model:the first response to the dynamic mechanical model:Sm=Si/1+k1t1the second response to the dynamic mechanical model:Se=Sm/ek2/2-Cthe k1=0.83326(h-1),k2= 0.05663(h-1).Through this model to predict the CODcr,the first reaction zone average relative error was only 9.43%,and the second reaction zone average relative error was 16.84%.It showed that the model precision was higher in the reactor with stable operation condition. |
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